Hybrid Compressor

ABSTRACT

A hybrid compressor has a first compression mechanism driven only by an external drive source; a second compression mechanism driven only by a built-in electric motor; suction paths for sucking gas to be compressed into the first compression mechanism; communication paths for sucking the gas from the first compression mechanism side into an electric motor side suction chamber; and suction passageways for sucking the gas from the electric motor side suction chamber to the second compression mechanism side. The positions and/or number of the communication paths and/or the suction passageways, and/or the positions and/or number of communication openings, which are openings of the communication paths and opened at the electric motor side suction chamber, and/or suction openings, which are openings of the suction passageways, opened at the electric motor side suction chamber, and located on a side opposite to the side of the communication openings, are limited so that, with respect to at least a part of the gas sucked into the electric motor side suction chamber via the communication paths, a gas flow is formed from the communication openings to the suction openings. In this structure, a built-in electric motor section can be appropriately cooled over a wider area by the sucked gas, so that a rise in temperature of the motor section can be properly suppressed.

TECHNICAL FIELD OF THE INVENTION

The present invention relates to a hybrid compressor in which a firstcompression mechanism driven by an external drive source and a secondcompression mechanism driven by a built-in electric motor are assembledintegrally and which is used in air conditioning systems for vehicles,etc., and specifically, to a hybrid compressor the motor section ofwhich can be cooled more effectively.

BACKGROUND ART OF THE INVENTION

Various proposals have been carried out for this type of hybridcompressors (for example, Patent document 1). A conventional hybridcompressor has a structure, for example, as shown in FIG. 1. Hybridcompressor 1 depicted in FIG. 1 is a scroll type compressor, and has afirst compression mechanism 2 and a second compression mechanism 3.First compression mechanism 2 has a fixed scroll 10, a movable scroll 11forming a plurality of pairs of operational spaces (fluid pockets) 12 byengaging with fixed scroll 10, a drive shaft 13 driving movable scroll11 at an orbital movement by engaging with movable scroll 11, anelectromagnetic clutch 15 for an on-off operation of the transmission ofa driving force between a pulley 14, to which the driving force from adrive source for running a vehicle (not shown) provided as an externaldrive source is transmitted via a belt, and the drive shaft 13, a ballcoupling 16 for preventing the rotation of movable scroll 11, and asuction port 18 formed on a casing 17. The gas to be compressed (forexample, refrigerant) sucked from suction port 18 into a suction chamber20 through a suction path 19 is taken into operational spaces 12, theoperational spaces 12 are moved toward the center of fixed scroll 10while the volumes of the operational spaces 12 are decreased, and bythis operation, the refrigerant gas in the operational spaces 12 iscompressed. A discharge hole 21 is formed on the central portion offixed scroll 10, and the compressed refrigerant gas is discharged to ahigh-pressure side of an external refrigerant circuit through thedischarge hole 21, a discharge path 22 and a discharge port 23.

On the other hand, second compression mechanism 3 has a fixed scroll 30,a movable scroll 31 forming a plurality of pairs of operational spaces(fluid pockets) 32 by engaging with fixed scroll 30, a drive shaft 33driving movable scroll 31 at an orbital movement by engaging withmovable scroll 31, and a ball coupling 34 for preventing the rotation ofmovable scroll 31. An electric motor 35 is incorporated in order todrive the drive shaft 33 of this second compression mechanism 3.Electric motor 35 has a rotor 36 fixed to drive shaft 33 and a stator 37having a motor coil part, the stator 37 is fixed to a stator housing 38or a stator housing 38 which is formed as a part of the compressorhousing, and the whole of electric motor 35 is contained in the statorhousing 38. An electricity is supplied to electric motor 35 via a powersupply portion 50. In this second compression mechanism 3, the gas to becompressed (for example, refrigerant) sucked from suction port 18 intosuction chamber 20 of first compression mechanism 2 is sucked into asuction chamber 40 of second compression mechanism 3 and a portion ofelectric motor 35 (an electric motor side suction chamber) through acommunication path 39. The gas sucked into suction chamber 40 of secondcompression mechanism 3 is taken into operational spaces 32, theoperational spaces 32 are moved toward the center of fixed scroll 30while the volumes of the operational spaces 32 are decreased, and bythis operation, the refrigerant gas in the operational spaces 32 iscompressed. A discharge hole 41 is formed on the central portion offixed scroll 30, and the compressed refrigerant gas is discharged to thehigh-pressure side of the external refrigerant circuit through thedischarge hole 41 and a discharge path 42.

Fixed scroll 10 of first compression mechanism 2 and fixed scroll 30 ofsecond compression mechanism 3 are disposed back to back, and both fixedscrolls 10 and 30 are formed as an integrated fixed scroll member 43. Inthis example, communication path 39 is formed in this fixed scrollmember 43.

In the hybrid compressor 1, when first compression mechanism 2 is onlyoperated, an electricity is not supplied to electric motor 35 fordriving second compression mechanism 3, and the electric motor 35 is notrotated. Therefore, second compression mechanism 3 does not operate.When the hybrid compressor 1 is driven only by electric motor 35, theelectric motor 35 is turned to be on and rotated, the rotation of theelectric motor 35 is transmitted to drive shaft 33 of second compressionmechanism 3, and the orbital movement of movable scroll 31 is performedby the drive shaft 33. At that time, electromagnetic clutch 15 of firstcompression mechanism 2 is not excited, and the rotation of the drivesource for running a vehicle as a first drive source is not transmittedto the first compression mechanism 2. Therefore, first compressionmechanism 2 does not operate. When both first and second compressionmechanisms 2 and 3 are driven simultaneously, the driving force from thedrive source for running a vehicle is transmitted to movable scroll 11of first compression mechanism 2 as well as electric motor 35 is turnedto be on and the driving force thereof is transmitted to movable scroll31 of second compression mechanism 3.

In the hybrid compressor 1 thus constructed, the control for switchingbetween first compression mechanism 2 and second compression mechanism 3and for simultaneous operation is performed in accordance with the loadcondition for cooling, etc. For example, in a light load condition wherea great cooling ability is not required in a vehicle interior, a soleoperation mode of the motor side having a small displacement (that is,second compression mechanism 3 side), or a simultaneous operation mode,in which the external drive source side having a great displacementrelative to the motor side (that is, first compression mechanism 2 side)is rotated at a low rotational speed and the motor is also operated, isemployed. The motor is operated through the control of the rotationalspeed, for example, by duty controlling the pulse voltage applied to themotor from a high voltage part in accordance with the demand from anexclusive drive control circuit. The motor coil part has a resistance,an electric current flows through the resistance, and the motor coilpart is heated. The motor coil part is cooled by the passage of therefrigerant or by the thermal transmission from the motor coil part tothe stator housing side and the heat radiation from the stator housingto the atmosphere, etc. The temperature of the motor coil part isdecided depending upon the balance between the amount of theabove-described heating and the amount of the above-described heatradiation. In the operational mode of sole drive of the motor side(second compression mechanism 3 side) or the simultaneous operationalmode where first compression mechanism 2 is driven at a low rotationalspeed and second compression mechanism 3 is also driven, when the amountof the above-described heating of the motor coil part exceeds the amountof the above-described heat radiation (for example, when the vehiclecondition is turned from a highway running in a summer time to a vehiclestopping and idling in a parking zone), the temperature of the motorcoil part may exceed an acceptable temperature, and at worst, theinitiation of the motor may be damaged. Therefore, it is necessary toproperly cool the motor portion including the motor coil part so thatthe temperature thereof does not exceed the acceptable temperature.

From the viewpoint described above, in particular, from the viewpoint ofimprovement of the cooling ability of the motor portion, a structure isknown wherein the refrigerant sucked through the communication path issucked into the suction chamber of the electric motor side, andtherefrom, sucked into suction chamber 40 of second compressionmechanism 3. For example, as depicted in FIG. 2, a structure is employedwherein the refrigerant sucked into suction chamber 20 of firstcompression mechanism 2 via suction path 19 is sucked into electricmotor side suction chamber 51 through a communication path 52 extendedup to the electric motor side suction chamber 51 (a communication pathcorresponding to communication path 39 depicted in FIG. 1), therefrigerant is used for cooling the motor by being passed through thevicinity of motor 35, and therefrom, the refrigerant is sucked intosuction chamber 40 of second compression mechanism 3 via suctionpassageway 53.

In the motor cooling structure using the refrigerant as shown in FIG. 2,the respective members have been structured, for example, as shown inFIGS. 3 to 6. FIGS. 3 and 4 depict an example of a center plate 54provided between electric motor side suction chamber 51 and secondcompression mechanism 3, and to this center plate 54, communicationpaths 52 having communication openings 55 as openings at electric motorside suction chamber 51, and suction passageways 53 having suctionopenings 56 as openings at electric motor side suction chamber 51, areprovided. As shown in FIG. 4, communication openings 55 and suctionopenings 56 are almost over the entire circumference.

Further, FIGS. 5 and 6 depict an example of a fixed scroll member 57which is formed by forming a fixed scroll of first compression mechanism2 and a fixed scroll of second compression mechanism 3 integrally in aform of back to back, and in this fixed scroll member 57, communicationpaths 52 are provided in the circumferential direction as shown in FIG.6. Where, symbols 58 represent bolt holes which are provided at fourpositions in the circumferential direction.

However, in the conventional hybrid compressor having the structure asdepicted in FIGS. 3 to 6, as shown by arrows in FIG. 2, the refrigerantgas sucked into electric motor side suction chamber 51 from suctionchamber 20 side of first compression mechanism 2 through communicationpath 52 and communication opening 55 is likely to be sucked to suctionopening 56 which is located at a closest position relative to thecommunication opening 55, and therefrom, the refrigerant gas is suckedinto suction chamber 40 of second compression mechanism 3 via suctionpassageway 53. Therefore, in a place apart from these communicationopening 55 and suction opening 56, there is a fear that the refrigerantgas stays in electric motor side suction chamber 51. As a result, amotor portion, which is positioned apart from these communicationopening 55 and suction opening 56, may not be cooled sufficiently by thesucked gas, and it may be overheated.

Patent document 1: JP-A-2004-278339

DISCLOSURE OF THE INVENTION Problems to be Solved by the Invention

Accordingly, an object of the present invention is to provide astructure of a hybrid compressor which can appropriately cool a sectionof a built-in electric motor over a wider area by sucked gas, therebysuppressing a rise in temperature of the motor section more properly,and further thereby making it possible to enlarge an available motoroperational range.

Means for Solving the Problems

To achieve the above-described object, the present invention provides ahybrid compressor has a first compression mechanism driven only by anexternal drive source, a second compression mechanism driven only by abuilt-in electric motor, a suction path for sucking gas to be compressedinto the first compression mechanism, a communication path for suckingthe gas from the first compression mechanism side into an electric motorside suction chamber, and a suction passageway for sucking the gas fromthe electric motor side suction chamber to the second compressionmechanism side, and the hybrid compressor is characterized in thatpositions and/or number of the communication path and/or the suctionpassageway, and/or positions and/or number of a communication opening,which is an opening of the communication path that is opened at theelectric motor side suction chamber, and/or a suction opening, which isan opening of the suction passageway that is opened at the electricmotor side suction chamber and located on a side opposite to the side ofthe communication opening, are limited so that, with respect to at leasta part of the gas sucked into the electric motor side suction chambervia the communication path, a gas flow is formed from the communicationopening to the suction opening.

In this hybrid compressor, a structure may be employed wherein thecommunication opening is provided only at a position on one side in theelectric motor side suction chamber, and the suction opening is providedonly at a position on a side opposite to the above-described one side inthe electric motor side suction chamber.

Further, a structure may be employed wherein the communication opening,the communication path, the suction passageway and the suction openingare provided at plurality conditions, respectively.

Further, a structure may be employed wherein a center plate is providedbetween the electric motor side suction chamber and the secondcompression mechanism, and the communication opening and the suctionopening are formed on the center plate.

Furthermore, a structure may be employed wherein a fixed scroll of thefirst compression mechanism and a fixed scroll of the second compressionmechanism are integrally formed as a common fixed scroll member, and apart of the communication path is formed on the fixed scroll member.

Where, as the external drive source, a drive source for running avehicle (including both an engine such as an internal combustion engineand an electric motor for running a vehicle in a case of an electriccar, etc.) can be employed. Further, as the gas to be compressed,refrigerant can be employed.

In such a hybrid compressor according to the present invention, when arise in temperature occurs in the built-in electric motor, particularlyin its coil portion, by the heating accompanying with increase ofelectric current, an excessive rise in temperature of the motor sectionmay be appropriately suppressed as follows. Namely, in theaforementioned conventional structure, because the sucked gas is likelyto flow from the communication opening at the electric motor sidesuction chamber to the suction opening located at the closest position,the sucked gas is liable to stay in a motor portion apart from bothopenings and the motor portion becomes hard to be cooled, and therefore,the motor section may be overheated. In the present invention, however,by disposing the communication path, particularly, the communicationopening, and the suction passageway, particularly, the suction opening,at positions opposite to each other, the sucked gas flowing from thecommunication opening to the suction opening flows over a wide areawithout staying, the motor is properly cooled over a wide area, andoccurrence of an overheating may be prevented. Further, as the resultthat the motor is appropriately cooled over a wide area, the availableoperational range of the motor can be enlarged.

Effect According to the Invention

Thus, in the hybrid compressor according to the present invention, thesucked gas for cooling can be flowed over a wide area in the electricmotor side suction chamber without being stayed, the whole of the motorcan be appropriately cooled, and a rise in temperature of the motor atthe time of motor operation can be suppressed low. Therefore, occurrenceof an inconvenience accompanying with an overheating of the motor can beavoided, and the available operational range of the motor can beenlarged.

BRIEF EXPLANATION OF THE DRAWINGS

FIG. 1 is a vertical sectional view of a conventional hybrid compressor.

FIG. 2 is a schematic vertical sectional view showing an example of astructure for cooling a motor section in the conventional hybridcompressor.

FIG. 3 is a schematic vertical sectional view showing an example of acenter plate in the structure depicted in FIG. 2.

FIG. 4 is an elevational view showing an example of the disposition ofcommunication openings and suction openings of the center plate depictedin FIG. 3.

FIG. 5 is a schematic vertical sectional view showing an example of afixed scroll member in the structure depicted in FIG. 2.

FIG. 6 is an elevational view showing an example of the disposition ofcommunication paths of the fixed scroll member depicted in FIG. 5.

FIG. 7 is a schematic vertical sectional view showing an example of astructure for cooling in a hybrid compressor according to an embodimentof the present invention.

FIG. 8 is an elevational view showing an example of the disposition ofcommunication paths of a fixed scroll member in the structure depictedin FIG. 7.

FIG. 9 is an elevational view showing an example of the disposition ofcommunication openings and suction openings of a center plate in thestructure depicted in FIG. 7.

EXPLANATION OF SYMBOLS

-   1: hybrid compressor-   2: first compression mechanism-   3: second compression mechanism-   10: fixed scroll-   11: movable scroll-   13: drive shaft-   14: pulley-   15: electromagnetic clutch-   16: ball coupling-   18: suction port-   19: suction path-   20: suction chamber-   21: discharge hole-   22: discharge path-   23: discharge port-   30: fixed scroll-   31: movable scroll-   33: drive shaft-   34: ball coupling-   35: electric motor-   36: rotor-   37: motor coil part (stator)-   38: stator housing-   39: first communication path-   40: suction chamber-   41: discharge hole-   42: discharge path-   43: fixed scroll member-   50: power supply portion-   51: electric motor side suction chamber-   52: communication path-   53: suction passageway-   61: communication path-   62: communication opening-   63: suction passageway-   64: suction opening-   65: fixed scroll member-   66: portion which is not provided with communication path and    communication opening-   67: center plate-   68: suction opening-   69: suction passageway-   70: portion which is not provided with suction opening and suction    passageway

THE BEST MODE FOR CARRYING OUT THE INVENTION

Hereinafter, desirable embodiments of the present invention will beexplained referring to figures.

FIG. 7 depicts a structure of a hybrid compressor according to anembodiment of the present invention, in correspondence with FIG. 2aforementioned. Since the structure depicted in FIGS. 1 and 2 is appliedcorrespondingly to the basic structure of the hybrid compressor depictedin FIG. 7, the explanation will be omitted by attaching the same symbolsas those attached in FIGS. 1 and 2 to the portions having substantiallysame structures as those shown in FIGS. 1 and 2. Hereinafter, pointsdifferent from the structure shown in FIGS. 1 and 2 will be mainlyexplained. Where, the arrows depicted in FIG. 7 show an example of arefrigerant gas flow at the time of motor operation.

The structure depicted in FIG. 7 is different from the structuredepicted in FIG. 2, in that communication paths 61 for sucking the gasto be compressed, which has been sucked from suction path 19 intosuction chamber 20 of first compression mechanism 2 (in this embodiment,low-temperature refrigerant gas before compression), into electric motorside suction chamber 51, and/or, communication openings 62 which areopenings of the communication paths 61 at electric motor side suctionchamber 51, and, suction passageways 63 of the refrigerant gas fromelectric motor side suction chamber 51 to suction chamber 40 of secondcompression mechanism 3, and/or, suction openings 64 which are openingsof the suction passageways 63 at electric motor side suction chamber 51,are disposed at positions apart from each other in the electric motorside suction chamber 51, particularly, at positions opposite to eachother.

For example, as an example of a fixed scroll member 65 in thisembodiment is shown in FIG. 8 in correspondence with FIG. 6aforementioned, communication paths 61 are provided only at the upperportion depicted in FIG. 8, and the communication paths 61 are notprovided for the lower and side portions 66 depicted in FIG. 8, in whichcommunication paths 52 have been provided in FIG. 6. Namely, in thestructure for disposing communication paths 52 in FIG. 6, thecommunication paths 52 are abolished in these portions 66. Accompanyingwith this disposition of communication paths 61, communication openings62, which are openings of the communication paths 61 at electric motorside suction chamber 51, are also provided only at the upper portiondepicted in FIG. 8, and they are not provided at positions correspondingto the above-described portions 66.

Further, for example, as an example of a center plate 67 in thisembodiment is shown in FIG. 9 in correspondence with FIG. 4aforementioned, suction openings 68 and suction passageways 69 areprovided only at the lower portion depicted in FIG. 9, and the suctionopenings 68 and suction passageways 69 are not provided for the upperportions 70 depicted in FIG. 9, in which suction openings 56 and suctionpassageways 53 have been provided in FIG. 4. Namely, in the structurefor disposing suction openings 56 and suction passageways 53 in FIG. 4,the suction openings 56 and suction passageways 53 are abolished inthese portions 70.

Thus, for electric motor side suction chamber 51, particularly thepositions and/or numbers of communication openings 62 and suctionopenings 68 are limited, and in particular, they are located atpositions opposite to each other. By this, the refrigerant gas suckedfrom communication openings 62 and flowing to suction openings 68 inelectric motor side suction chamber 51 flows over a wide area withoutstaying, as shown in FIG. 7.

Consequently, motor 35 can be appropriately cooled over the entire area,and a rise in temperature of the motor 35 at the time of motor operationcan be suppressed low. Therefore, occurrence of the inconvenienceaccompanying with an overheating of the motor can be avoided, and theavailable operational range of the motor can be enlarged.

INDUSTRIAL APPLICATIONS OF THE INVENTION

The present invention can be applied to any hybrid compressor into whicha first compression mechanism and a second compression mechanism areintegrally incorporated and the second compression mechanism of which isdriven by a built-in electric motor.

1. A hybrid compressor having a first compression mechanism driven onlyby an external drive source, a second compression mechanism driven onlyby a built-in electric motor, a suction path for sucking gas to becompressed into said first compression mechanism, a communication pathfor sucking the gas from said first compression mechanism side into anelectric motor side suction chamber, and a suction passageway forsucking the gas from said electric motor side suction chamber to saidsecond compression mechanism side, characterized in that positionsand/or number of said communication path and/or said suction passageway,and/or positions and/or number of a communication opening, which is anopening of said communication path that is opened at said electric motorside suction chamber, and/or a suction opening, which is an opening ofsaid suction passageway that is opened at said electric motor sidesuction chamber and located on a side opposite to the side of saidcommunication opening, are limited so that, with respect to at least apart of the gas sucked into said electric motor side suction chamber viasaid communication path, a gas flow is formed from said communicationopening to said suction opening.
 2. The hybrid compressor according toclaim 1, wherein said communication opening is provided only at aposition on one side in said electric motor side suction chamber, andsaid suction opening is provided only at a position on a side oppositeto said one side in said electric motor side suction chamber.
 3. Thehybrid compressor according to claim 1, wherein said communicationopening, said communication path, said suction passageway and saidsuction opening are provided at plurality conditions, respectively. 4.The hybrid compressor according to claim 1, wherein a center plate isprovided between said electric motor side suction chamber and saidsecond compression mechanism, and said communication opening and saidsuction opening are formed on said center plate.
 5. The hybridcompressor according to claim 1, wherein a fixed scroll of said firstcompression mechanism and a fixed scroll of said second compressionmechanism are integrally formed as a common fixed scroll member, and apart of said communication path is formed on said fixed scroll member.6. The hybrid compressor according to claim 1, wherein said externaldrive source is a drive source for running a vehicle.
 7. The hybridcompressor according to claim 1, wherein said gas to be compressed isrefrigerant.